The present invention relates to the scheduling of movement of plural units through a complex movement defining system, and in the embodiment disclosed, to the scheduling of the movement of freight trains over a railroad system and specifically to the scheduling of linked resources.
Systems and methods for scheduling the movement of trains over a rail network have been described in U.S. Pat. Nos. 6,154,735, 5,794,172, and 5,623,413, the disclosure of which is hereby incorporated by reference.
As disclosed in the referenced patents and applications, the complete disclosure of which is hereby incorporated herein by reference, railroads consist of three primary components (1) a rail infrastructure, including track, switches, a communications system and a control system; (2) rolling stock, including locomotives and cars; and, (3) personnel (or crew) that operate and maintain the railway. Generally, each of these components are employed by the use of a high level schedule which assigns people, locomotives, and cars to the various sections of track and allows them to move over that track in a manner that avoids collisions and permits the railway system to deliver goods to various destinations.
As disclosed in the referenced patents and applications, a precision control system includes the use of an optimizing scheduler that will schedule all aspects of the rail system, taking into account the laws of physics, the policies of the railroad, the work rules of the personnel, the actual contractual terms of the contracts to the various customers and any boundary conditions or constraints which govern the possible solution or schedule such as passenger traffic, hours of operation of some of the facilities, track maintenance, work rules, etc. The combination of boundary conditions together with a figure of merit for each activity will result in a schedule which maximizes some figure of merit such as overall system cost.
As disclosed in the referenced patents and applications, and upon determining a schedule, a movement plan may be created using the very fine grain structure necessary to actually control the movement of the train. Such fine grain structure may include assignment of personnel by name, as well as the assignment of specific locomotives by number, and may include the determination of the precise time or distance over time for the movement of the trains across the rail network and all the details of train handling, power levels, curves, grades, track topography, wind and weather conditions. This movement plan may be used to guide the manual dispatching of trains and controlling of track forces, or may be provided to the locomotives so that it can be implemented by the engineer or automatically by switchable actuation on the locomotive.
The planning system is hierarchical in nature in which the problem is abstracted to a relatively high level for the initial optimization process, and then the resulting course solution is mapped to a less abstract lower level for further optimization. Statistical processing is used at all levels to minimize the total computational load, making the overall process computationally feasible to implement. An expert system is used as a manager over these processes, and the expert system is also the tool by which various boundary conditions and constraints for the solution set are established. The use of an expert system in this capacity permits the user to supply the rules to be placed in the solution process.
Currently, online real-time movement planners do not have the capability to identify and accommodate linked train movements. Linked trains are trains in which the movement of one or more trains is dependent on the movement of at least one other train. Typical scenarios of linked movements include (a) meet/pass—the first train to arrive at the meet or pass location must wait for passage of the train being met before it proceeds, (b) block swap—a train scheduled to pick up a block of cars cannot do so until another train has arrived and set them out, (c) middle annul (train combination)—A portion of a train's route may be annulled and its consist assigned to another train which requires that the combined train (the train into which the consist is consolidated) cannot depart until the annulled train has arrived with the car blocks and the annulled train cannot resume its route past the annulled portion until the combined train has arrived and set out the car blocks, and (d) helper train—if a train has insufficient power for grade, a helper locomotive is assigned to assist which requires that the assisted train cannot depart the helper cut-in location until arrival of the helper train, and the helper train cannot depart the helper cut-out location until arrival of the assisted train.
Typically, linked train movements required manual intervention by a dispatcher or could be accommodated grossly by offline static planners by setting desired arrival and departure times in the case of block swaps. The linked train scenarios are difficult to accommodate in the train movement plan not only because the departure of one train is dependent upon the arrival of another train, but also because a dwell time may be required to perform the pickup or setout.
Another linked scenario which could not be accommodated by prior art movement planners is when all or part of a consist is moved between linked trains resulting in a change in the trains' characteristics. For example, when a consist having a high priority is picked up by a train having a lower priority, there has been no mechanism for automatically changed the priority of the train to reflect the addition of the higher priority consist.
The current disclosure provides a system and method of incorporating train movement linkage in the planning algorithm so that the planned movement of a linked train takes into account the movement of the train to which it is linked. Additionally, the present system and method can dynamically adjust train characteristics at linkage points.
These and many other objects and advantages of the present invention will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the embodiments.